Floating throat knife



Sept. 29, 1970 3,531,106

c. A. LARSON ET AL FLOATING THROAT KNIFE Filed Aug. 22, 1968 2 Sheets-Sheet 1 INVENTOR CURTlS A. LARSON RICHARD J. ULLMER ATTORNEYS.

Sept. 29,1970 v Q LARSON ErAL FLOATING THROAT KNIFE Filed Aug. 22, 1968 2 Sheets-Sheet FIG. 3

FIG. 4

s m w W V 3 mm L A w T R U C RICHARD J. ULLMER ATTORNEYS United States Patent 3,531,106 FLOATING THROAT KNIFE Curtis A. Larson and Richard J. Ullmer, Rochester, Minn., assignors to International Business Machines Corporation, Armonk, N.Y., a corporation of New York Filed Aug. 22, 1968, Ser. No. 754,643 Int. Cl. B65h 3/06, 9/16 US. Cl. 271-36 11 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention This invention relates to card feed mechanisms and more particularly to top feed mechanisms in which a stack of cards are biased against a card pick device overlying the stack, and in which the top card is fed forwardly through upper and lower knife members forming a throat gap which will pass a single card of given thickness.

Description of the prior art Card feed mechanisms of the top feed type have long been employed for feeding, in serial fashion, cards from a stack. Biasing means continuously load the card stack against card pick means whereby, regardless of stack depletion, the card picker is periodically actuated to feed the cards, one at a time, in serial fashion along a horizontal feed path.

In order to prevent the feeding of more than one card at a time, there is normally provided means defining a feed throat at the forward end of the pack which accepts the upper-most card, but rejects the next card thereunder. Conventionally, the cards are fed from the top by either an oscillating picker or by a driven friction roller. The picker may contact the cards at a localized area only, for instance to one side of the stack, causing the uppermost card to bow laterally during the moment of feeding. Further, the individual cards themselves may be warped and thus, the uppermost card may spring back into a warped position prior to feeding since it is no longer under restraint of the cards above it. K

To compensate for bowing or warping of the uppermost card, attempts have been made to automatically adjust the position of one or more members defining the throat gap with the top of the stack to compensate for card warping while at the same time, insuring that the top card only is being fed forwardly through the throat gap. The prior art devices, while compensating somewhat for card warpage, have been unable to maintain a constant throat gap dimension which results in an inadvertent multiple card feed.

SUMMARY OF THE INVENTION This invention is directed to the top feed mechanism for a card stack employing a throat knife assembly which readily accepts warped cards. With the stack of cards being biased against an overlying card picker, the throat knife assembly, comprisin upper and lower throat knives to form a throat gap of constant dimension is pivotably supported on one side of the card stack for limited movement about an axis parallel to and generally aligned with the plane of card feed.

Specifically, upper and lower pivot arms are coupled to the card stack hopper back plate by a piece of polypropylene plastic which acts as a pivot flexure. In rest position, and in the absence of a card stack, the flexure allows the upper throat knife to move to a position slightly lower than the extreme card warp position. With a card stack in place, the upper throat knife contacts the top card and rests thereon. Therefore, regardless of card warpage from the plane of card feed, in either an up or down direction, the upper throat knife follows the warpage of the card to present the constant dimension throat feed gap in align ment with the leading edge of the card being fed. The upper throat knife may be adjustably coupled to the upper pivot arm to allow initial variance in the throat gap dimension.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of the floating throat knife of the present invention as applied to a top feed mechanism for a card stack.

FIG. 2 is a rear elevational view of the floating throat knife assembly of FIG. 1 in the absence of a card stack taken about lines 22.

FIG. 3 is a similar view of the floating throat knife to that of FIG. 2, with the upper throat knife resting on the top card stack whose edges are warped upwardly.

FIG. 4 is a similar view of the floating throat knife as that of FIG. 2, with the upper throat knife resting upon the top card of the stack whose edges are bowed downwardly.

FIG. 5 is a perspective view of the plastic flexure of the present invention for pivotably mounting the improved floating throat knife assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, a typical top card feed apparatus 10 includes a plate or other support 12 which carries card stack 14 consisting of a number of thin planar information bearing cards or the like 16. The top or upper most card of the stack is identified at 16 and is in a position for forward feeding, the direction of card flow being indicated by arrow 18. In conventional fashion, the card stack is biased upwardly against a card feed pick mechanism 20. Biasing is indicated schematically by coil spring 22 acting in the direction of arrow 24. While the plane of card feed may be stated as being generally horizontal, it is noted that the card stack 14 is slightly inclined downwardly in the direction of card feed.

The card pick mechanism 20 may comprise, for instance, an oscillating pick arm although, in the illustrated embodiment, a friction roller 26 has its periphery in contact with the upper surface of the top card 16. With the friction roller 26 being driven in a clockwise direction as indicated by arrow 28, the top card 16 will be fed forwardly, from right to left through throat knife assembly 30 at the forward end of the card feed apparatus. The pick roller 26 is mounted for rotation about its axis and supported by hopper back plate 32 by means (not shown).

The present invention is directed to the floating throat knife assembly 30 which includes lower throat knife 34 and upper throat knife 36 defining a throat knife gap 38 of constant dimension W, preferably slightly greater than the thickness of one of the cards 16, but being less than the thickness of two cards. Thus, the cards 16 are fed in serial fashion through the throat gap 38 which will allow passage of only one card at a time. A common mounting plate 40 carries upper pivot arm 42 and lower pivot arm 44 which acts as a bracket to support respectively, upper throat knife 36 and lower throat knife 34. Since the card feed mechanism may feed cards of varying thickness the upper pivot arm 42 carries a guide pin 46 which projects,

from the rear face thereof, through an elongated, generally vertical slot 48 formed centrally of the upper throat knife 36. Further, a threaded screw 50 and washer 52 are carried on the upper pivot arm, the shank of the screw being freely received within slot 48 and being threadably engaged to the upper pivot arm 42. As such, loosening of screw 50 allows the upper throat knife 36 to be adjusted vertically, relative to its supporting pivot arm 42. Therefore, the gap 38 existing between the upper and lower throat knives may be readily adjusted without changing the relationship between the upper and lower pivot arms 42 and 44. Unlike the prior card feed mechanisms, the throat knife assembly 30 of the present invention is pivotally mounted for limited oscillation about an axis which is parallel to, and generally in line with the path of card feed through throat gap 38.

This is achieved through the employment of a pivot flexure 54 which is best seen in FIG. 5. The pivot flexure 54 comprises a rectangular piece or block of plastic material such as polypropylene and includes an upper, rather thick rectangular section 56 separated from a lower, somewhat thinner, rectangular section 58 by a thin connecting strip 60. Strip 60 is formed by longitudinally grooving the area of juncture between these two sections as at 62. Thus, the weakened or reduced thickness section 60 defines the horizontal pivot axis which is generally in line with the plane of card feed indicated in dotted line fashion at 64 in FIGS. 2, 3 and 4 and which also coincides with the position of the uppermost or top card 16' of the stack.

For coupling the pivot flexure 54 to the hopper back plate 32 and plate 40 coupling the upper and lower pivot arms 42 and 44, there are provided paired apertures 66 in upper flexure section 56 and paired apertures 68 in lower section 58. The hopper back plate 32 is also apertured at 70 and threaded screws 72 pass through respective apertures 66 and 70 and carry threaded nuts 74. Washers 76 are also provided to insure proper positioning of the flexure 54 and maintenance of the same in position on the hopper back plate. In similar fashion, threaded screws 78 are threadably coupled to rear plate 80 after passing through an associated aperture 82 of support plate 40 and aligned aperture 68 of the lower flexure section 58. Again a washer 84 is positioned on the outside of mounting plate 40 for assisting in coupling flexure 54 to the mounting plate 40.

When there are no cards in the machine, the floating throat knife assembly 30, including upper and lower pivot arms 42 and 44 and plate 40, pivots under gravity as shown in FIG. 2. The contact edge 86 of the upper throat knife moves to its lowest point which is slightly lower than the lowermost position of a card in extreme card warped condition. When the card stack 14 is spring-loaded, in the direction of arrow 24, against the friction feed roller 26 of card pick mechanism 20, the surface of the card being fed such as card 16' at its front end, abuts edge 86 of the upper throat knife 36. This causes the throat knife assembly 30 to pivot about the pivot axis defined by strip section 60 of the pivot flexure, moving the throat gap 38 into a generally horizontal position in the absence of card warpage. The gap, however, aligns itself with the card irrespective of any warped condition since the edge 86 of the upper throat knife 36 rides on the upper surface of card 16' as indicated in FIG. 1.

Assuming that the uppermost card 16' is bowed into a concave warped position, looking up from the bottom of the stack, FIG. 4, edge 86 of the upper throat knife 36 which rides upon the upper surface of card 16' moves through the plane 64 of normal card feed in a clockwise direction as the throat knife assembly pivots about section 60 of the flexure pivot. Note, however, that the gap 38 is longitudinally aligned with the edge of the card being fed therethrough to allow only the single card 16' to be fed with the vertical, rear face 88 of the lower throat knife 34 acting as a card stop and preventing forward feeding of the remaining cards 16 of stack 14 which are at that 4 moment positioned below the plane of normal card feed indicated by dotted line 64.

Referring next to FIG. 3, if the uppermost card 16' were bowed or warped upwardly, that is warped into convex configuration as seen from the bottom of the stack, the contact surface or edge 86 of the upper card throat knife again rests on the upper surface of card 16' but in this case, this contact edge 86 moves below the normal plane of card movement as defined by dotted line 64. Again, the gap 38 between the upper and lower throat knives is in alignment with the leading edge of the card 16' being fed, and will not obstruct that particular card although, the leading edges of the remaining cards of the stack again abut rear contact face 88 of the lower throat knife 34.

In either case, regardless of the extreme warped conditions of a card or a group of cards within the stack, there is no mis-match of the card edge and the throat knife during selective, serial feeding of the top card. The flexure acting as a pivot, automatically allows the upper throat knife 36 to fall down on the top card presenting the throat gap adjacent to the card and in line with the edge. The pick action of friction roller 26 then drives the aligned card through the gap. It may be necessary to employ a biasing force on the pivoted throat knife assembly to maintain the upper throat knife contact surface 86 against the uppermost card depending upon the center of gravity of the card feed and the transport mounting angle. Further, while the illustrated embodiment employs a rectangular flexure strip or piece of plastic such as polypropylene it is obvious that plastic materials other than polypropylene may be substituted therefor, or alternatively a rubber strip may be employed. Further, it is envisioned that a simple pivot axis may be defined for the fixedly coupled upper and lower pivot arms by employing a pivot pin or other element mounted for assembly pivot about a horizontal axis parallel to the axis of card feed. Further, with the exception of the pivot flexure 54, the elements of the floating throat knife assembly 30, may be formed of metal or plastic material.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that the foregoing and other changes in form and detail may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In a card feed mechanism including means for biasing a stack of cards against a card pick device contacting the uppermost card of the stack, the improvement comprising:

(a) a throat knife assembly including upper and lower throat knives defining a throat gap of constant dimension, and

(b) means for pivotably supporting said throat knife assembly for limited rotation about an axis parallel to the plane of card feed, and generally in line therewith and in the path of card feed with the upper throat knife riding on the upper-most card.

2. The card feed mechanism as claimed in claim 1 wherein said means for pivotably supporting said throat knife assembly comprises a bracket including upper and lower pivot arms, a fixed supporting member to one side of said stack and a strip of flexible material, one end of which is fixedly coupled to said supporting member and the other end being coupled to said bracket.

3. The card feed mechanism as claimed in claim 1 further including means for adjusting the position of one of said throat knives with respect to its pivot arm whereby, the dimension of said throat gap between said upper and lower throat knives may be readily varied.

4. In a card feed mechanism of the type wherein a stack of cards are biased against pick means contacting the uppermost card of the stack, the improvement comprising:

(a) a throat knife assembly including upper and lower knives forming a throat gap of fixed dimension, and

(b) means for pivotably supporting said knife assembly with the upper throat knife resting on the top of the stack with the gap in the path of card feed and for oscillation about a pivot axis laterally spaced, and generally in line with the card feed path.

5. The card feed mechanism as claimed in claim 4 wherein, said throat knife assembly comprises bracket means having upper and lower pivot arms fixedly coupled to a plate lying laterally to one side of the feed path, and said pivot support means comprises a fiexure block, one end of which is coupled to said bracket plate.

6. The card feed mechanism as claimed in claim 5 wherein said flexure block is grooved longitudinally in the direction of card feed to form a thin section which acts as the pivot axis for said assembly.

7. The card feed mechanism as claimed in claim 6 further including; a fixed side plate defining the lateral limit of the card feed path at right angles to the bracket pivot arms, and parallel to the fixed side plate, and means for fixably coupling the other end of said flexure block to said side plate.

8. The feed mechanism as claimed in claim 5 wherein said fiexure block is formed of polypropylene plastic material.

9. The card feed mechanism as claimed in claim 7 wherein said flexure block is formed of polypropylene plastic material.

10. The card feed mechanism as claimed in claim 4 further including means for mounting said pivotable throat knife assembly such that the contact surface of the upper throat knife lies below the plane of card feed in absence of a card stack.

11. The card feed mechanism as claimed in claim 7 further including means for mounting said pivotable throat knife assembly such that the contact surface of the upper throat knife lies below the plane of card feed in the absence of a card stack.

References Cited UNITED STATES PATENTS RICHARD E. A'EGERTER, Primary Examiner US. Cl. XJR. 271-52 Disclaimer 3,531,106.0urs A. Larson and Riclzami J. UZZmer, Rochester, Minn.

FLOATING THROAT KNIFE. Patent dated Sept. 29, 1970. Disclaimer filed July 1, 1974, by the assignee, International Business M (whines Corporation. Hereby enters this disclaimer to claims 1, 3, 4 and 10 of said patent.

[Oficz'al Gazette April 22, 1.975.] 

